Selective flotation of minerals.



KARL SUNDERG, OF STOCKHOLM, SWEDEN.

SELECTIVE FLOTATION OF MINERALS.

Specification of Letters Patent.

Patented nee. so, i919.

Application led March 19. 1918. Serial No. 223,380.

To all 107mm it may concern:

Be it known that l, KARL SUxnnnuc, a subject ot' the King ot' Sweden, residingl at Stockholm, Sweden, have invented certain new and useful Improvements in Selective F lotation of Minerals, of which the follow ing is a specification. f

My invention refers to a process of separating from a mineral, for instancean ore or a small ore, containing one or more floatable minerals, each of' these minerals per se. `With the term fioatable minerals I mean such minerals which in mixture in a finely divided state with a liquid and foam producing means, after forcing air or another gas through the mixture are raised with the foam produced to the surface of the mixture. The process is practicable for instance for the separation of galena and Zinc-blende in a small ore containing these minerals, specular iron ore and copper pyrite in a cuprous red hematite ore, or galena, zinc-blends and copper pyrite in a small orecontaining these minerals.

The invention is based upon the difierent disposition of the different minerals to rise with the foam produced, in such a manner'that in the treatment of an ore containingseveral minerals in a flotation apparatus with several compartments or chambers the foam in the first chamber or chambers will contain essentially greater quan-v tities of the more iioatable mineral than of the other one, which latter mineral will accumulatein the foam, produced in the last chamber or chambers. In fact the proportion of the quantities of the different minerals in the foam from the different chambers can be determined once for all, because under forthe rest equal circumstances this proportion is proportional to the proportion of the mineral components of the material to be treated in the apparatus. If thus in the treatment in a flotation apparatus l.with several chambers of an ore mixture, containing 25% of each of two minerals, the foam in the first chamber contains 50% of the one and 5% of the other mineral, t-he proportion of the minerals in the foam in the treatment of an ore mixture containing` 30% of the first mentioned mineral and 10% of the ymineral last mentioned becomes=50:--g=30: 1 in place of the proportion 50 :5 first mentioned.

The invention consists therein that the mineral. mixture in the usual manner is floated in a flotation apparatus with several chambers or compartments, whereupon the foam from the first and last chamber or from some of' the first and the last chambers ot' this apparatus (the said foam thus containing either of the minerals in a great quantity) is brought respectively into the first chamber of two other flotation apparatus where it is floated anew and the product thus obtained from the first chamber of the one of these apparatus and from the last chamber of the other apparatus is let off and collected, while the foam from the intermediate chambers of the flotation ap aratus is brought `back to the first chamber of the apparatus first mentioned or to the first chambers in each apparatus and then submitted again to iiotation.

In the accompanying drawing Figures l and 2 are schematic views showing two processes embodying my invention. The process illustrated in Fig. l is applied to a material containing two minerals in equal pro ortions. For carrying out the process at rst for instance three apparatus divided in fi've chambers or compartments a, b, o, are used.

In the flotation in the apparatus a the two minerals distribute themselves in the foam for instance in the proportion 1:4 in the first chamber, 1:2 in the second chamber, 1:1 in the third chamber, 2:1 lin the fourth chamber and Lirl in the fifth chamber, as shown in the drawing. From the first chamberof the apparatus @the foam produced is carried to the first chamber of the apparatus 5, where a concentration of the mineral easiest to float takes place. This mineral, which now is very pure from the other one (for instance in the proportion 16: l) is removed, and the remaining mineral is floated in the other chambers of the apparatus b. The foam produced by this latter flotation as also the foam obtained in the chambers 2-4 of the apparatus a, is brought back to the first chamber' of the said apparatus a or to the first chamber of the apparatus f) and again submitted to flotation. In the same manner thev foam from the last chamber 5 o-f the apparatus a is brought to the first chamber of the third apparatus c, where it is floated again. From the last chamber 5 of'that apparatus the foam rich in the second mineral is removed, while the foam from the other chambers in the apparatus c is brought to the first chamber of the apparatus a or to the first chamber of the apparatus c,

' of the apparatus b is brought `back lto the` `als The foam from an intermediate chamber 3 in the apparatuses b and c can also be brought back to the first chamber 1 in these apparatuses in place of to the chamber 1 in the apparatus a. In Fig. 1 the approximate proportions of the minerals at different stages' of the flotation is shown, and the courses in which the foam is brought from the different apparatus are marked with arrows. 1

In this way a separation of the minerals can be produced, so that the small ore from the first chamber of the apparatus b contains 16 parts of the one mineral against 1 part Vot the other one, while the small ore from the last chamber of the apparatus c contains 1 part of the mineral first mentioned on 1G parts of the other one. By using still more .fiotation apparatuses a further concentration of course is obtainable.

'Fig 2 illustrates, also schematically, the process applied to a material, containing three minerals of diierent adaptability for flotation. In thiscase more apparatuses/z,

b, c', d, e, f-than now described. are used. p

The ore is first oated in the-apparatus a,

y whereby the foam from the first chamber of this apparatus is brought into the first chamber of the next apparatus Za, while the foam from the last chamber of the apparatus a` -is brought into the first chamber of the apparatus 0. The foam from the other chambers 2-4 of the apparatus a is brought back to the first chamber of this apparatus and Y fioated again. The foam from the lfirst chamber I1in the apparatus b (which foamy contains the mineral easiest to ioat) is collected and the foam from the last chamber 5 of the same apparatus, b is brought to the first chamber 1 of an apparatus c, While the foam from the intermediate chambersQ-t first chamber 1 of the apparatus b or the first chamber of the apparatus a, where it is again submitted-to flotation.V In the sameA manner the foam from the first chamber of the apparatus c is brought into the first chamber of the apparatus e, while the foam ffrom the last chamber 5 of the apparatus 0,

which foam is rich i'n the mineral most difficult to ioat, is4 removed andv collected. The foam from the intermediate chambers 2--4 .of the apparatus c is brought .back to the first chambery of the apparatus a or 0, the

foam from the latter as also from the last' chamber of the apparatus b containing more ofthe mineral having an adaptability for 'float is removed and collected together withl the material from the first chamber 1 of 'floated a ain, and from the last chamber 5 of the said apparatus the foannrich in the mineral most diiicult to float is removed and collected together with that from the last chamber of the apparatus c. As well in the apparatus d as in e and f the foam from the chambers 2-1 is brought back to the chamber 1 in each such apparatus. The mineral with a floatability between that of the two other minerals, is contained in the foam obtained in the last chamber of the apparatus d and the first chamber of the apparatus f, for which reason' that foam is removed separately, so that'the said mineral can be col- -lected from the foam. Of course it is possiblealso in the process now described to .complete the enriching of the minerals from the ore, by increasing the number of apparatus used.

From the examples given it is evident,

that according tothe present invention it is always `possible in the iotation apparatuses with several compartments or chambers to separate the oatablecomponents of the ma- .teral by ioating anew the foam from the first and last chamber or chambers per se in other flotation apparatuses, in which the foam from the first chamber of the one apparatus and from the last chamber of the othei apparatus is collected as a finished productor is again floated. in other apparatuses, while the foam from the intermediate chambers (between the first and the last chamber or chambers) is oated again in the same or' in a preceding ap aratus.

Having now particularly descri ed the natureof my invention and` the manner of itsc operation, what I claimis: r

l. A' vprocess for separating minerals by iotation which consists in pulping the ore; ltreating the same in flotation apparatuses with several compartments in such a manner that the foam. from the firstcompartment and that from the last compartment of oneapparatus is floated again per se in a further flotation apparatus,-while the foam from the intermediate compartments of each apparatus after the initial treatment apparatus is brought back to and oated in the',

rst compartment in one of the otation apparatlis.

apparatus yis floated again per se in a further flotation apparatus, while the foam from the intermediate compartments of each appa-` process vfor separating minerals by flotation which consists in pulping the ore;

ratus is brought back to and oated in the rst compartmentin one of the dotation apparatus, and the material which has not been taken up by the foam from the ast compartment of the rst apparatus is brought to and floated in a second apparatus, whereupon the foam produced at this otation is collected vtogether With that previously obtained and submitted to repeated dotations, the non-oatahie material remain" 10 ing being collected per se.

In testimony whereof -I have affixed my signature in presence of two Witnesses.

KARL SUNDBERG.

Vtnesses S. MAGNUssoN, H. TELANDER. 

